Record-Breaking, Dangerous Heat Wave to Impact Midwest, Northeast

The Northeast is in for heat as we get into the weekend and at least the start of next week. While the forecast becomes somewhat uncertain by the Fourth of July, we are certain that it will get very hot across the northeastern US beginning this weekend. Thermometers for millions of people will measure temperatures into the 90s and even the 100s in some towns. It will also be humid. Heat indices will also get into the 90s and 100s, reaching dangerous levels.

Before the heat reaches the Northeast, it will impact the Midwest and surrounding areas. All sorts of heat alerts are in place from the local National Weather Services offices. That induces widespread Heat Advisories as well as an Excessive Heat Watch for Chicago and nearby areas and an Excessive Heat Warning in and around Kansas City.

The developing heat dome will traverse across the Central US on Thursday. Geopotential heights will near 594 decameters, translating to a very strong area of upper-level high pressure. When heights are greater, that translates to a warmer air mass. Once heights get into the 590s, that often means very hot conditions. In some heat events, heights can surpass 600 decameters, which is unusual even in the midsts of summer. In this scenario, temperatures typically near or achieve record levels.

Under the heat dome there will be high temperatures ranging from 5 to 25 degrees above normal. The warmest of temperatures relative to normal will be in the Central Plains where highs will be in the 90s and 100s. Denver, known for its wild temperature swings, is forecast to experience a high temperature of 103 degrees, which would break their daily record high. Across the rest of the Central US, highs will be in the 80s, 90s, and 100s. That heat will also sneak into the Southeast with widespread highs into the 90s and near 100 degrees while the Northeast enjoys their last seasonable day.

The heat dome will continue to track east on Friday, bringing high temperatures into the 90s to much of the Midwest, Great Lakes, Southeast, and Mid-Atlantic. The Central and Southern Plains will be baking with actual high temperatures mainly in the 100s. Surprisingly, no cities are forecast to break a record high on Friday. Meanwhile to the north and west, a cold front will gradually cool down to the front range of the Colorado Rockies and the Northern Plains.

By the weekend, it will be the Northeast’s turn for the heat. The Midwest through the Northeast will generally experience temperatures between 5 and 15 degrees above average, translating to highs into the 90s for most. About a dozen cities are expected to break their daily record high as well. The Southern Tier will cool off by a few degrees but will remain around 5 degrees above average with highs also in the 90s — a few 100s will be sprinkled in there as well.

This slight decrease in temperatures on Saturday across the South is due to the position of the heat dome. By this point in time, the center, or the area of greatest heights, will be over the Northeast. The ridge will also be even stronger with heights likely exceeding 594 decameters. That is almost record-breaking for parts of the region, reaching the 99.5th percentile. That translates to a very hot air mass.

Credit: Tomer Burg

Not only will it be hot. It will also be humid. We have bee focusing on the actual temperature, but the feels-like temperatures will be even higher into the 90s and 100s thanks to dew points into the 60s and 70s, which is indicative of a very moist air mass. These feels-like temperatures are actually more important than the actual because the feels-like gives your body a better scale of how it may be able to handle the heat.

The heat will persist into Sunday. While highs in the 80s invade the Northern Plains and Upper Midwest, high temperatures into the 90s will persist across the eastern Great Lakes, Ohio River Valley, Northeast, Mid-Atlantic, and Southern Tier. The heat dome will remain centered over the northeastern US, however, so that’s where the warmest of temperatures relative to average will be. Highs will be up to 25 degrees above normal in the region, which is substantial when it occurs during the hottest time of the year, or now. Record high temperatures will be broken in numerous locations once again, and some cities will get into the low 100s.

Monday will be a transition day as this first ridge weakens over the Northeast and drifts to the east. Meanwhile, over the nation’s heartland, a new ridge will slowly develop, which may bring the most widespread and intense heat wave to the nation. Coast-to-coast above average temperatures are becoming increasingly likely, but we’ll focus on this next heat event in a different article. Before then, it will remain quite toasty across much of the Eastern US on Monday. Most of the Northeast, Mid-Atlantic, and Southern Tier can expect another day with highs in the 90s. The immediate coastline will remain up to 5 to 10 degrees cooler due to the proximity of the cool ocean, especially in New England. Some areas will have to opportunity to hit 100 degrees in the I-95 corridor. On the other hand, temperatures will be seasonable in the Northern and Central Plains and Midwest with highs mainly in the 80s. There will be some towns that will creep a bit further into the low 90s.

By Tuesday, it will remain hot across much of the Eastern and Central US with highs 5 to 15 degrees above average as the new heat dome develops with heights increase to around 595 decameters. Highs across the Eastern Seaboard will generally be in the 80s and 90s while very hot air streams in from the south across the Plains. Highs in this part of the country will get into the 90s and 100s while it’s in the 80s and 90s across much of the Northern Plains and Midwest.

On the Fourth of July, it will turn very hot nationwide. Now while it’s too early to get too detailed into this forecast, high temperatures will be above average across most of the country with the exception of the West Coast. Many locations will experience highs in the 80s, 90s, and 100s along with high humidity east of the Rocky Mountains. Hopefully, you’re ready to deal with days of sweltering conditions as this long-duration heat wave takes place. Be sure to stay safe out there because this heat may turn deadly.

Jackson is Head of Content at WeatherOptics and produces several forecasts and manages all social media platforms. Previously, Jackson forecasted local weather for southwestern Connecticut, founding his website, Jackson's Weather, in the March of 2015. He is currently studying Meteorology and Broadcast Journalism at the University of Miami.